Open Caching and CDN standards: The role of the SVTA and IETF

A discussion with Jay Robertson, System Architect, Qwilt

The success of the commercial internet has been aided in large part by standards. Early foundational work, such as Transmission Control Protocol/Internet Protocol (TCP/IP), became standardized when the Internet was the Advanced Research Projects Agency Network (ARPAnet) in 1983. As the Internet has grown, various industry associations feeding into international bodies, such as the Institute of Electrical and Electronics Engineers (IEEE) and the Internet Engineering Task Force (IETF), have helped to define distinct standards for everything from Wi-Fi to common email protocols like POP.

With so much of today’s internet traffic flowing across some form of Content Distribution Network (CDN), it is surprising that CDN operation has relatively few agreed standards. Instead, many CDNs today are primarily proprietary services – with a few adopting APIs to allow for some degree of integration and interoperability.

For this blog, we spoke with Jay Robertson, System Architect for Qwilt, who has been working in a development role, which include supporting efforts by the SVTA and the IETF to help advance a true open standard within the CDN space.

What are some of the challenges faced by the CDN industry?

Jay Robertson: In the CDN industry, I would say that most of the integration work is directly between content providers and their CDN vendors; generally, these are not based on standards. There are several large CDN vendors, and several solutions have been designed to work with these technologies for certain use cases, but if a content provider wants to change CDN provider, they need to go through another bespoke integration process. In some cases, this might mean multiple integrations with many different CDNs. This web of customized integration limits flexibility and innovation and creates unnecessary complexity along with unwanted vendor lock-in, often leading to technical issues as CDN features and architectures change over time. Indeed, some CDN vendors have used this to their advantage in the past. Standardization, especially the work of the SVTA and IETF, proposes an inherently better option for CDNs and their customers.

What is the Streaming Video Technology Alliance Open Caching concept?

JR: The SVTA’s work on Open Caching is focused on establishing recommendations and best practices around architecture and functionality. With this approach, the SVTA’s Open Caching initiative fulfills the industry’s need for a configuration metadata model and standard API that builds upon the work in the IETF’s Content Delivery Networks Interconnection (CDNI) working group. Then, these recommendations become more official specifications as they get contributed back to CDNI and make their way through the IETF standards process. The SVTA’s Open Caching working group includes the participation of experts from over a dozen companies, including Qwilt, Verizon, Hulu, Disney, Broadpeak, Lumen, Viasat, Vecima, Telefonica, and many others.

Open Caching is not exclusively for video, but considering that by some estimates, 80% of content volume across the Internet is video, this has been the primary application and the first deployed use case. Service providers are highly incentivized to deploy Open Caching to better control the traffic and reduce the load of redundant video streams across their networks. Without it, popular live video streaming events and VOD titles consume significant bandwidth and network resources, increasing network expansion costs and reducing service quality for all end users. So, video is a big driver for this reason.

Where are we today with Open Caching?

JR: CDNs adhering to the SVTA Open Caching standards have been deployed by multiple vendors since 2021. During 2021/2022, an Open Caching Testbed Initiative witnessed multiple CDN operators demonstrate the capacity for their CDN solutions to be provisioned for streaming delegation within an Open Caching Network by exposing the SVTA’s Open Caching API (server-side) in the testbed and showing correct operation between their systems and the testbed.

Regarding commercial Open Caching deployments, Qwilt leads the industry, having onboarded over 150 service providers who have each deployed open caches based on the SVTA specification in their respective networks. Serving over one billion unique subscribers globally, Qwilt Open Cache partners include major service providers such as Verizon in North America; TIM Brazil and Telecom Argentina in Latin America; Airtel and J:COM in Asia-Pacific; and BT, Telefonica, and Vodafone Turkey in EMEA and many, many more.

Is Open Caching evolving?

JR: Within the SVTA working group, Open Caching is progressing towards a 2.0 release. There will be several significant announcements in the coming months.  Many great improvements are coming, such as using BNF as a grammar to define syntax, better convenience functions, reduced complexity in private features, improved implementation guidelines, significant enhancements in logging, and security by design through the safe handling and transmission of encrypted secrets. Another area that is undergoing development is the idea of named footprints. This allows a content provider to gain an exact idea of what footprint capacity is available via API from a particular provider so that it can make more intelligent routing decisions among its CDN providers.

Where is Open Caching in terms of becoming a more widely adopted standard?

JR: There is now strong cooperation between the SVTA and the IETF around using the rapid adoption of Open Caching to extend the initial work that the IETF started over a decade ago with its CDNI working group. This cooperation would build on the CDNI efforts to add Open Caching as an IETF standard.

In recent years, there has been recognition that CDNs and Open Caching Systems have similar configuration metadata definitions and challenges, so both groups have aligned to tackle them together in a single standard. The SVTA is now actively contributing its extensions to the IETF to be incorporated into the CDNI standard.  More work has been accomplished in the last two years than most of the previous eight, and a positive outcome may become a reality relatively soon.

In part two of this blog, we will talk to Sanjay Mishra from Verizon to look at Open Caching from the perspective of a major telecommunication operator.